Gorrelation of solubilities of goal liquefaction products in supercritical gases

Solubilities of coal liquefaction products in supercritical gases have been correlated by using a perturbed-hard-sphere equation of state^{1) ～3)} given by Eq. (2). Mixing rules based on the local mole fraction concept were adopted. The mixing rules, given by Eqs. (7) ～(12), have been previously found to correlate successfully high-pressure vapor-liquid equilibria for asymmetric mixtures such as CO₂-methanol system. The properties of pure gases and solids which are objects of this study are presented in Tables 1 and 2. The calculated results for single gas-single solid systems are shown in Table 3 with the values of characteristic binary parameters α₁₂ and k₁₂ adjusted to best represent the experimental results. Further, solubilities of single gas-mixed solid systems were correlated and correlation performance is shown in Table 4 and a typical illustration is given in Fig. 1. These results demonstrate a relatively good agreement. Solubilities of the present systems can be correlated also by use of empirical mixing rules previously reported.^5),6) However, the present mixing rules based on the local mole fraction concept are more useful when these are applied to multicomponent systems. That is because no multicomponent parameter is needed. It should be noted that one cannot obtain a good correlation by use of the widely adopted conventional mixing rules.^5),6).